MR imaging of the arthritic knee: improved discrimination of cartilage, synovium, and effusion with pulsed saturation transfer and fat-suppressed T1-weighted sequences.

Objective: To assess the applicability of three-dimensional (3D) magnetic resonance (MR) imaging with pulsed saturation transfer (ST) or fat saturation in depicting articular structures in arthritic knees.

Methods: Eleven patients underwent MR imaging with T1-weighted spin-echo (SE); unenhanced and contrast material-enhanced T2*-weighted 3D gradient-echo with and without on-resonance pulsed ST; and T1-weighted, fat-presaturated 3D gradient-echo techniques. Images with ST were subtracted from those without ST.

Results: Both fat-suppressed imaging and ST-subtraction (STS) techniques generated a high contrast-to-noise ratio among cartilage, synovium, effusion, bone, and adipose tissue. Both techniques depicted hypertrophic synovial tissue on unenhanced images; contrast material was necessary to differentiate between synovium and cartilage on STS images.

Conclusions: 3D MR imaging with fat-suppressed or STS techniques provides good discrimination among articular structures in arthritic knees. Fat-suppressed imaging is faster than STS imaging and offers better contrast between cartilage and synovium. These techniques may improve monitoring of arthritic disease progression and therapeutic response.